Deregulation of STAT-5 isoforms in the development of HPV-mediated cervical carcinogenesis

Methods: A total of 120 fresh cervical tissue specimens comprising precancer (n = 12), cancer (n = 78) and normal controls (n = 30) were analyzed for HPV infection and expression pattern of STAT-5 mRNA (both isoforms STAT-5a and STAT-5b) and protein in different stages of cervical carcinoma biopsies by reverse-transcriptase-PCR, western blotting and immunohistochemistry. Results: A significantly increased expression of STAT-5 was detected in most of the cervical tumors (P < 0.001), whereas it was almost undetectable in normal controls. Also the study of relative contribution of STAT-5 isoforms revealed a higher expression pattern of STAT-5b and was associated with severity of the disease. On the contrary, STAT-5a was found to be significantly downregulated in cervical tumor tissues (P < 0.001). HPV infection was found in 90% of the cervical cancer cases and was significantly associated with STAT-5 overexpression (P = 0.001). Conclusions: We observed for the first time the differential expression pattern of STAT-5 isoforms in cervical cancer and that STAT-5 may play an important role in the progression of HPV-mediated cervical cancer.